Automatic provisioning of power parameters for femtocell

ABSTRACT

Automatic provisioning of an access point base station or femtocell. The method may include the femtocell transmitting first information (e.g., location information, signal measurement information, capability information, etc.) to a service provider (e.g., over an IP network). The femtocell may receive second information from the service provider, where the second information includes one or more operational parameters. The operational parameters may include hand-off parameters, admission policy parameters, PN or scrambling codes, power parameters, and/or other parameters. The femtocell may operate according to the received parameters to provide access for a plurality of access terminals in a local area.

PRIORITY INFORMATION

This application claims benefit of priority of U.S. provisionalapplication Ser. No. 60/977,655 titled “Femto-Cell to Marco-CellHandoffs and Interference Mitigation” filed Oct. 5, 2007, whoseinventors are Stash Czaja, Anthony S. Lee, and Mark Davis, which ishereby incorporated by reference in its entirety as though fully andcompletely set forth herein.

FIELD OF THE INVENTION

The present invention relates to the field of cellular networks, andmore particularly to automatic provisioning of a femtocell base station.

DESCRIPTION OF THE RELATED ART

In recent years, the use of mobile devices and, in particular, cellulartelephones has proliferated. As a result, focus on reception forcellular telephones or other mobile devices, especially in homes orprimary residences, has increased. Additionally, typical users of mobiledevices use or subscribe to data services for their homes. As a result,femtocells (more generally called access point base stations) have begunto be used in the home. Femtocells provide cellular service to mobiledevices using the data service of the user. Thus, these femtocellsprovide excellent service where mobile devices are used most andtypically make use of data plan services (e.g., DSL, fiberoptic, cable,WiMAX, etc.), which may not require a nearby macro cell of the cellphone service provider. However, femtocells typically require manual setup, e.g., by a technician, in order to operate efficiently. Thus,improvements in installation of femtocells would be desirable.

SUMMARY OF THE INVENTION

Various embodiments are presented of a method for automaticallyprovisioning an access point base station (e.g., a femtocell).

Various embodiments are presented of a method for automaticallyprovisioning an access point base station (e.g., a femtocell) to reduceinterference of the access point base station.

The access point base station may provide wireless communication in awireless area while a service provider (e.g., via a macro base station)may provide wireless communication in a macro area. The access pointbase station may include an interface with one or more wired or wirelessports for coupling to a wide area network and/or to access terminals(e.g., mobile devices). Additionally, the access point base station mayinclude one or more processors and memory to implement various ones ofthe processes described below.

The access point base station may provide wireless communication in alocal area. In some embodiments, the access point base station mayperform one or more measurements, e.g., of signals (e.g., signalstrength) provided by the one or more access terminals.

The access point base station may connect to the service providerthrough a wired connection (e.g., an IP connection over a wide areanetwork) and transmit first information. The first information mayinclude location information, capability information, the measurementinformation, and/or other information of the access point base station.The capability information may include propagation characteristics ofthe environment in which the access point base station is located. Theaccess point base station may sent an activation request message (ARM)followed by the first information to the service provider.

In response, the access point base station receiving second information(e.g., in the form of or in addition to an assignment message) from theservice provider. The second information may include one or moreoperational or provisioning parameters which may be determined based onthe first information provided by the access point base station. In oneembodiment, the plurality of parameters may include at least one handoffparameter. The at least one handoff parameter may include a macro toaccess point base station drop threshold and an access point basestation to macro drop threshold. In some embodiments, the secondinformation and/or the handoff parameter(s) may include hysteresisinformation. The handoff parameters/hysteresis information may bedetermined or provided regardless of the location of the access pointbase station within the macro coverage area. The handoff parameter(s)may be determined based on the location information, the capabilityinformation, and/or the measurement information.

Alternatively, or additionally, the plurality of parameters may includepower parameters, such as a maximum transmit power parameter. Themaximum transmit power parameter may define a coverage area (thecoverage area is larger than or equal to the local area) of the accesspoint base station. In some embodiments, the power parameters (e.g., themaximum transmit power parameter) may contain information or definepower allocation of one or more overhead channels of the access pointbase station. The power parameters may be determined based on thelocation information, the capability information, and/or the measurementinformation, among other information. In some embodiments, the one ormore operational parameters (e.g., power transmit parameters or handoffparameters) may be determined based on a coverage area propagationmodel.

Correspondingly, the access point base station may operate based on theone or more operational parameters. Operating based on the operationalparameters may reduce the interference produced by the access point basestation and/or may allow for more efficient handoffs between the macrobase station and the access point base station.

For example, the access point base station may receive signal strengthinformation from an access terminal moving from the macro area to thelocal area. When the signal strength information indicates that thesignal strength of the access point base station is above the macro toaccess point base station drop threshold (indicated above), the accesspoint base station may send a handoff request to the service provider.Correspondingly, the handoff request may cause the access terminal tobegin using the access point base station (e.g., by removing the macrobase station from the active set of the access terminal). Similarly, theaccess point base station may receive signal strength information froman access terminal moving from the local area to the macro area. Whenthe signal strength information indicates that the signal strength ofthe macro base station is above the access point base station to macrodrop threshold (indicated above), the access point base station may senda handoff request to the service provider. Correspondingly, the handoffrequest may cause the access terminal to begin using the macro basestation (e.g., by removing the access point base station from the activeset of the access terminal).

The second information may further include admission policy informationincluding an admission policy mode specifying one or more of open,restricted, or private access to resources of the access point basestation. Additionally, the admission policy information may include aservice priority parameter for specifying service priority of aplurality of access terminals. The method may include the access pointbase station receiving user input specifying a list of access terminals,and the access point base station using the list of access terminals andthe admission policy mode to determine access to the access point basestation. However, the list of access terminals may be provided in thesecond information. Alternatively, or additionally, users may enter asecret code (e.g., using a first access terminal) to be added to theterminal list (e.g., by the access point base station receiving andstoring an identification of the first access terminal in a memorymedium) or to receive privileges of an access terminal on the list.

In one embodiment, the access point base station may use the list ofaccess terminals and the associated service priority parameter todetermine at least one of: 1) access or 2) access priority to the accesspoint base station. Additionally, or alternatively, operating based onthe parameters may include providing access to access terminals based onthe parameters (e.g., based on admission policy information).

In one embodiment, where the admission policy mode parameter indicates aprivate mode, the access point base station may only allow the accessterminals on the list to communicate or use resources of the accesspoint base station. In a restricted mode, access terminals on the listmay be enabled to communicate with or use the access point base station,e.g., with priority over those access terminals not on the accessterminal list.

In response to a change in the network (or possibly changes in admissionpolicies), the access point base station may receive updated operationalparameters from the service provider, and correspondingly operate basedon the updated operational parameters. The updated parameters mayinclude updated power parameters, handoff parameters, access policyparameters (or modes), etc. Similar to above operating based on theupdated operational parameters may reduce interference caused by theaccess point base station in the changed network and/or provide moreefficient handoffs in the changed network. Where the updated parametersinvolve the admission policy (e.g., the mode or access terminal list),the access point base station may provide access and/or services toaccess terminals based on this updated information.

Thus, the access point base station may be automatically configuredbased on first information transmitted by the access point base station.

BRIEF DESCRIPTION OF THE DRAWINGS

A better understanding of the present invention can be obtained when thefollowing detailed description of the preferred embodiment is consideredin conjunction with the following drawings, in which:

FIG. 1 is an exemplary system including an access point base stationaccording to one embodiment;

FIG. 2 is an exemplary general block diagram of the access point basestation according to one embodiment;

FIG. 3 is a flowchart of an exemplary method for automaticallyprovisioning the access point base station, according to one embodiment;

FIG. 4 is a graph illustrating handoff areas for a macro base stationand an access point base station, according to one embodiment;

FIG. 5 is a diagram illustrating service areas for a macro base stationand two access point base stations, according to one embodiment;

FIG. 6 is a flowchart of an exemplary method for performing a handoffbetween a macro base station and an access point base station, accordingto one embodiment;

FIG. 7 is a graph corresponding to the method of FIG. 7, according toone embodiment;

FIG. 8 is a flowchart of an exemplary method for performing a handoffbetween an access point base station and a macro base station, accordingto one embodiment;

FIG. 9 is a graph corresponding to the method of FIG. 9, according toone embodiment; and

FIG. 10 is a flowchart of an exemplary method for illustrating admissionpolicy according to one embodiment

While the invention is susceptible to various modifications andalternative forms, specific embodiments thereof are shown by way ofexample in the drawings and are herein described in detail. It should beunderstood, however, that the drawings and detailed description theretoare not intended to limit the invention to the particular formdisclosed, but on the contrary, the intention is to cover allmodifications, equivalents and alternatives falling within the spiritand scope of the present invention as defined by the appended claims.

DETAILED DESCRIPTION OF THE EMBODIMENTS Terms

The following is a glossary of terms used in the present application:

Memory Medium—Any of various types of memory devices or storage devices.The term “memory medium” is intended to include an installation medium,e.g., a CD-ROM, floppy disks 104, or tape device; a computer systemmemory or random access memory such as DRAM, DDR RAM, SRAM, EDO RAM,Rambus RAM, etc.; or a non-volatile memory such as a magnetic media,e.g., a hard drive, or optical storage. The memory medium may compriseother types of memory as well, or combinations thereof. In addition, thememory medium may be located in a first computer in which the programsare executed, or may be located in a second different computer whichconnects to the first computer over a network, such as the Internet. Inthe latter instance, the second computer may provide programinstructions to the first computer for execution. The term “memorymedium” may include two or more memory mediums which may reside indifferent locations, e.g., in different computers that are connectedover a network.

Programmable Hardware Element—includes various hardware devicescomprising multiple programmable function blocks connected via aprogrammable interconnect. Examples include FPGAs (Field ProgrammableGate Arrays), PLDs (Programmable Logic Devices), FPOAs (FieldProgrammable Object Arrays), and CPLDs (Complex PLDs). The programmablefunction blocks may range from fine grained (combinatorial logic or lookup tables) to coarse grained (arithmetic logic units or processorcores). A programmable hardware element may also be referred to as“reconfigurable logic”.

Program—the term “program” is intended to have the full breadth of itsordinary meaning. The term “program” includes 1) a software programwhich may be stored in a memory and is executable by a processor or 2) ahardware configuration program useable for configuring a programmablehardware element.

Software Program—the term “software program” is intended to have thefull breadth of its ordinary meaning, and includes any type of programinstructions, code, script and/or data, or combinations thereof, thatmay be stored in a memory medium and executed by a processor. Exemplarysoftware programs include programs written in text-based programminglanguages, such as C, C++, Pascal, Fortran, Cobol, Java, assemblylanguage, etc.; graphical programs (programs written in graphicalprogramming languages); assembly language programs; programs that havebeen compiled to machine language; scripts; and other types ofexecutable software. A software program may comprise two or moresoftware programs that interoperate in some manner.

Hardware Configuration Program—a program, e.g., a netlist or bit file,that can be used to program or configure a programmable hardwareelement.

Computer System—any of various types of computing or processing systems,including a personal computer system (PC), mainframe computer system,workstation, network appliance, Internet appliance, personal digitalassistant (PDA), television system, grid computing system, or otherdevice or combinations of devices. In general, the term “computersystem” can be broadly defined to encompass any device (or combinationof devices) having at least one processor that executes instructionsfrom a memory medium.

FIGS. 1 and 2—Exemplary Block Diagrams of a Communications System

FIG. 1 illustrates an exemplary system including an access point basestation (e.g., a femtocell). The term “access point base station” isintended to include typical definitions (as known by those of skill inthe art) of femtocells, home base stations, personal access points(PAPs), and personal 2G-3G (or nG) base stations, among others. In someembodiments, the access point base station may include capabilities of amobile station transmitter/receiver (transceiver) as well as furtherfunctionality described in more detail below. Various embodiments of amethod to automatically provision (i.e., setup) the access point basestation (e.g., by providing appropriate operational parameters) arepresented below.

As shown, FIG. 1 illustrates a home which may include one or more accessterminals 110, an access point base station 120, and a broadband device130. As shown in FIG. 2, the access point base station 120 may includebase station circuitry 200 which may be coupled to mobile stationtransceiver circuitry 250. The base station circuitry 200 and/or themobile station transceiver circuitry 250 may include or be coupled to aprocessor (not shown) and memory (not shown) coupled to the processor toimplement their functionality. In one embodiment, each of the basestation circuitry and the mobile station transceiver circuitry may haveindependent processors and memory; however, these components may share aprocessor and memory.

As shown in FIGS. 1 and 2, the base station circuitry 200 and the mobiletransceiver circuitry 250 may be included in a same housing of theaccess point base station 120. The housing may be plastic or metal(e.g., aluminum or other metals) and may take a box-like design. In oneembodiment, the housing may include one or more lights or light emittingdiodes (LEDs) which indicate the activity or operation of variouscomponents of the access point base station 120 (e.g., operation of thebase station circuitry 200 and/or the mobile station transceivercircuitry 250, among others).

The housing may include a power supply for providing power to thecomponents of the access point base station 120. The housing may alsoinclude one or more ports for coupling to other devices orcommunications devices. For example, in one embodiment, the housing mayinclude a universal serial bus (USB) port (or other type of port, suchas firewire, among others) for attaching devices (e.g., printers,personal music players, personal digital assistants, cell phones,external hard drives, testing devices, media controllers, etc.).Additionally, or alternatively, the one or more ports may includeEthernet ports (e.g., for coupling to a router or the communicationsdevice 130, among others), fiber ports, cable ports, etc. In someembodiments, the ports may be implemented as an interface or aninterconnection network coupled to the other devices via a wired orwireless connection.

The access point base station 120 may operate to receive wirelesscommunication (e.g., radio frequency (RF) communication) from the one ormore access terminals 110 and provide corresponding signals orcommunication with mobile operator(s) (or cellular service providers)corresponding to the providers of the access terminals 110. Morespecifically, the access point base station 120 may operate to providecommunication for the access terminals 110 using the broadbandcommunications device 130 over an IP wide area network 150 (e.g., theInternet, via the user's internet service provider (ISP)). The broadbanddevice 130 may thus communicate with the cellular service provider 160via the Internet.

Moreover, the IP wide area network 150 may be private or dedicated tothe user using various technologies, for example, lease line, framerelay, digital subscriber line (DSL), or dial-up service. The IPcommunication may be encrypted or IP tunneling may be used if supportedby the IP wide area network 150. The cellular service provider 160 mayalso be coupled to macro base stations 170 (sometimes referred to ascell phone towers or macro cell stations) which may operate to provideservice to the access terminals 110 when outside of range of the accesspoint base station 120 and/or when the access point base station 120 isdisabled or non-operational. Thus, the access point base station 120 mayprovide bi-directional communication for the access terminals via an IPnetwork such as the Internet. Stated another way, users in the home mayuse their cell phones which communicate with the access point basestation, wherein the user's voice communications may betransmitted/received to/from the cellular service provider over an IPnetwork.

The mobile station transceiver circuitry 250 may operate to communicatewith the access terminals 110 and the cell towers 170 using wirelesscellular communication such as RF. However, it should be noted that insome embodiments, the mobile station transceiver circuitry 250 may notcommunicate directly with the access terminals 110; instead, it mayreceive signals from the access terminals 110 via another component,such as the base station 200. The mobile station transceiver circuitry250 may be used for loopback testing, reporting of environmentalfactors, and to provide redundancy when the IP network is down, thusimproving cellular reception in the home. Thus, in some embodiments, themobile station transceiver circuitry 250 may be used to monitorenvironmental factors of the access point base station 120 (e.g.,neighboring macro cell stations, neighboring femtocells, radio frequencytraffic in the home, etc.) and may convey that information (e.g., to theservice provider via the macro cell station or the IP network, asdesired) for configuration of the access point base station 120. Thisinformation may be critical during initial (e.g., automatic) set up ofthe access point base station 120. Correspondingly, macro base station170 and/or the service provider 160 via the wide area network 150 maycommunicate with the access point base station 120 during installationof the access point base station 120 to perform set-up operations, e.g.,automatically. The mobile station transceiver circuitry 250 may alsoallow for initiation of testing (e.g., loop-back testing) of the accesspoint base station 120, e.g., in response to signals from the macro basestation 170.

The access terminals (also referred to as mobile terminals) 110 mayinclude any type of device which may be used in a cellular network,e.g., RF communication. Access terminals 110 may include cellular (orcell) phones (including smart phones), personal digital assistants(PDAs) with mobile communication capabilities, laptops or computersystems with mobile communication components, and/or any device which isoperable to communicate with a cellular network. The access terminalsmay use various different protocols, e.g., cdma2000 (1×RTT and EV-DO),UMB, UMTS, LTE, WiMax, or others). Thus, the access point base stationmay support any or at least a subset of the protocols used by the accessterminals 110, e.g., without modification to the standards or protocolsfor supporting existing access terminals.

The broadband device 130 may include a router and/or cable/dsl modem forconnecting to the wide area network 150. In one embodiment, thebroadband device 130 may include a wireless router (or one or morewireless hubs) which may provide wireless communication (e.g., using802.11× communication technology) for the access point base station 120.Additionally, the broadband device 130 may be connected to the wide areanetwork 150 via wired (e.g., cable, DSL, fiberoptic, power lines, etc.)or wireless means (e.g., WiMAX or other wireless communication methods),as desired. Alternatively, or additionally, the broadband device 130 maybe coupled to the access point base station 120 remotely, e.g., via aWiMAX wireless connection. Furthermore, in one embodiment, the accesspoint base station 120 may include the broadband device 130 (e.g., in anall-in-one solution for the user).

Thus, the access point base station 120 may provide access to thecellular network via the wide area network 150 (e.g., the Internet)using the broadband device 130 (wired or wirelessly) and may include themobile station transceiver 250.

FIG. 3—Automatic Provisioning of an Access Point Base Station

FIG. 3 illustrates an exemplary method for automatically provisioning anaccess point base station. The method shown in FIG. 3 may be used inconjunction with any of the computer systems or devices shown in theabove Figures, among other devices. In various embodiments, some of themethod elements shown may be performed concurrently, performed in adifferent order than shown, or omitted. Additional method elements mayalso be performed as desired. As shown, this method may operate asfollows. In the following description, references to the “access pointbase station” refer to the access point base station 120.

In 302, the access point base station may be installed, e.g., by a user,possibly in a home. However, installation may occur by a serviceprovider technician or other entity, as desired. Installation of theaccess point base station may include providing power to the accesspoint base station and coupling the access point base station to abroadband communications device (e.g., using wired or wireless means).In some embodiments, the user may only be required to provide power tothe access point base station and couple the access point base stationto the broadband device. In other embodiments, further connectionsettings may be required (e.g., to set up the wireless or networksettings of the access point base station). Furthermore, in someembodiments, the access point base station may be installed in a newlocation by moving the access point base station from an old location.In this example, one or more of the steps described below may not beperformed if such information has already been received from a previousinstallation (e.g., acquiring identification information as in 306).

The access point base station may be installed within or near a macroarea of a macro cell base station which provides wireless communicationin the macro area for the service provider. Thus, the access point basestation may provide wireless communication for the service providerwithin an access point base station coverage area (also referred aslocal area), possibly inside of or intersected partially with a macrobase station coverage area (also referred as macro area) provided by themacro base station. FIG. 4 shows a graph corresponding to this scenario.As shown, the access point base station coverage area is within themacro base station coverage area. The indicated region illustrates wherehandoffs between the access point base station and the macro basestation may occur, e.g., based on signal strength ratios. Furtherdescriptions of the handoff procedures are provided below.

FIG. 5 also illustrates a macro base station 502 which provides servicein a macro area 500 to access terminals within the macro area (such as,for example, access terminal 550). As shown, two access point basestations 510 and 515 may provide service in local areas 512 and 517.More specifically, access point base station (ap bs) 510 may provideservice for access terminal 552. As also indicated, there may bemacro-ap reverse and forward link interference for access terminal 554between the macro base station 502 and the access point base station 515as well as inter-ap forward and reverse link interference for accessterminal 556 between the access point base stations 510 and 515. Theseinterferences may be mitigated or managed according to various power,handoff, and hysteresis parameters, described in more detail below.

In 304, the access point base station may send a message or otherwiserequest automatic provisioning of the access point base station from awireless service provider. The message (and possibly other messagesdescribed below) may be defined as a new set of classes in the SNMP,CORBA, and XML models and may be administered over network managementprotocols, such as OAM, among other possibilities. In some embodiments,the access point base station may send the message over an IP network,e.g., provided by the broadband communications device. Alternatively (orpossibly if the broadband communications device is not currentlyproviding a network connection), the access point base station may sendthe message over the wireless network of the service provider, e.g.,using a neighboring macro base station or possibly another access pointbase station.

In 306, the access point base station may receive identity informationfrom the service provider. The identity information may uniquelyidentify the access point base station in the network of the serviceprovider, and may be used in requests between the service provider andthe access point base station. Further, the access point base stationmay receive the identity information from the service provider prior tothe access point base station connecting to the service provider throughthe wired connection.

In 308, the access point base station may transmit first information tothe service provider, e.g., in one or more messages, possibly includingan activation request message (ARM). The first information may beprimarily provided over the IP network, e.g., provided by the broadbandcommunications device. However, similar to descriptions above, the firstinformation may be provided via the macro base station of the serviceprovider, e.g., when the IP network is unavailable. The firstinformation may include identity information and/or a plurality ofparameters which describe various aspects of the access point basestation. For example, the plurality of parameters may indicate locationinformation, environmental information, capability information, and/orother information related to the access point base station. The firstinformation may further includes at least one measurement of signalsreceived by the access point base station from the macro base station,which will be provided to the service provider as a key factor ofdetermining the access base station coverage area.

More specifically, the first information may include the locationinformation of the access point base station, e.g., in terms of latitudeand longitude, among other possibilities. The location information maybe determined by the service provider and/or the access point basestation, e.g., using standard network assisted location procedures. Insome embodiments, the access point base station may determine itslocation information by communicating with a neighboring macro basestation (or a plurality of neighboring base stations), e.g., bydetermining offset information and the location of the neighboring basestation(s). Alternatively, in one embodiment, a GPS receiver may be usedto provide the location information (e.g., coupled to or comprised inthe access point base station).

As indicated above, the first information may further include capabilityinformation such as supported RAT technologies, maximum number of usersand data rates, cell coverage characteristics (e.g., to allow maximumpower allocation), etc. The capability information may includepropagation characteristics of the environment in which the access pointbased station is located; however, this information may also or insteadbe provided in the environmental information parameters. One or moreportions of the first information (e.g., environmental characteristics,location information, offset information, etc.) may be determined usinga mobile station transceiver of the access point base station.

In 310, the access point base station may receive an assignment messagefollowed with second information from the service provider (e.g., overthe IP network) which includes information and/or one or moreoperational parameters. In 310 the access point base station may receivethe second information (including the operational parameters) and storethe operational parameters in the appropriate memory location in thebase station such that these parameters may be accessed and used bysoftware executing on the base station. Thus, receipt and storage of theoperational parameters may automatically provision or configure theaccess point base station without any direct or manual user inputrequired (other than connecting the base station to power and abroadband connection).

The second information may be determined (by the service provider) basedon the first information (e.g., measurement information, locationinformation, signal measurement and/or other information) provided bythe access point base station. The operational parameters may includehand off parameters for handling handoffs of access terminals betweenthe access point base station and the macro cell base station. In oneembodiment, the second information may include an access point basestation frequency or channel(s) assignment, a network SID and/or NID,and/or the identification of the access point base station, amongothers. The second information may include a PN offset (for cdma2000protocols) and/or a cell scrambling code (for UTMS). The PN offsetand/or cell scrambling code may be based on the location of the accesspoint base station and may be used to manage the interference of theaccess point base station to the surrounding network.

The second information may include a neighbor list, which may include alist of neighboring macro base stations and/or other access point basestations. As indicated above, the second information may include PNoffsets (e.g., long and/or short PN offsets) or scrambling code(s) forUMTS. These may be used to aid in the interference management of theaccess point base station. In some embodiments, the neighbor list may beupdated whenever the neighbor list changes and/or at various periodictime intervals. The second information may include additional parameterssuch as access point base station time re-sync (which may be sent by thenetwork upon a loss of link(s) synchronization with the neighbornetwork), channels assignments (CAM messages which may be used to aid inthe interference mitigation management of the access point basestation).

The second information may further include handoff offsets or parametersrelated to handoffs, which may indicate macro to access point basestation drop threshold(s) and/or access point base station to macro dropthreshold(s). For example, the second information may provide handoffoffset (HO) thresholds and hysteresis information, e.g., to facilitatehandoff regardless of the access point base station within the macrocoverage area.

The HO thresholds may comprise handoff parameters, such as macro toaccess point base station (or femto) drop threshold “MSFDT_(DROP) ” andaccess point base station to macro drop threshold “F2FDT_(DROP) ”, amongothers. The MSFDT_(DROP) parameter may specify a signal strength ratioused to determine when to perform a handoff from the macro base stationto the access point base station when an access terminal is moving fromthe macro area (service being provided by the macro base station) to thelocal area. Conversely, the F2FDT_(DROP) parameter may specify a signalstrength ratio used to determine when to perform a handoff from theaccess point base station to the macro base station when an accessterminal is moving from the local area (service being provided by theaccess point base station) to the macro area.

The hysteresis information may comprise one or more parameters thatindicate a history of which of the macro base station or the accesspoint base station has most recently provided service to the accessterminal. In one embodiment, a positive (e.g., in dB) value ofMSFDT_(DROP) parameter provides a hysteresis during the macro-to-femtoHO, while a negative value of F2FDT_(DROP) provides hysteresis duringthe femto-to-macro HO. Those hysteresis may protect against frequentswitching (ping-pong), between macro and femto service.

In one embodiment, the parameters may relate to optimal HO completiontime or thresholds related to the time of HO completion. The HOparameters may help secure seamless HOs to/from other base stations,help reduce interference to the remaining users and/or surroundingnetwork, and/or improve system capacity and overall quality of serviceby reducing the number of active code channels. These operationalparameters/information (and possibly other parameters) may besemi-static and valid until the next message is sent from the serviceprovider and/or until other changes in the location, environment, and/oruser settings (among others) of the access point base station. Furtherdescriptions regarding hand offs between the access point base stationand a neighboring base station are provided in further flowcharts below.

The second information may further include a maximum transmit powerparameter which may be used to defines a coverage area for the accesspoint base station and control the interference of the access point basestation to the surrounding network (e.g., macro base stations or otheraccess point base stations which may be indicated in the neighbor list).The coverage area defined by the maximum transmit power parameter islarger than or equal to the local area (e.g. actual coverage area) ofthe access point base station. The maximum power parameter(s) may bedetermined based on the desired coverage area of the access point basestation as well as the desired quality of service (e.g., for the user'shome). The power parameter(s) may also be determined based on thelocation information of the access point base station, measurements ofsignals received by the access point base station, capabilityinformation of the access point base station, and/or other factors. Themaximum transmit power parameter may include information specifyingoverhead channels power allocation (e.g., PiCH for the 1×RTT), etc. Insome embodiments, the maximum transmit power parameter (and theoperational parameters of the second information) may be determinedusing a coverage area propagation model. For example, this determinationamong others of the information and operational parameters may beperformed or determined by one or more servers of the service provider.

The coverage area propagation model may include a series of typicalresidence/office layouts including such parameters as: type—destandalone/attached/apartment; area, number of rooms and levels; constructiontype—concrete, wood, cardboard, etc. Those typical layouts may beincluded in an installation SW (disc). Various procedures and theparameters (area, construction type, etc) may be entered by the user (ordetected or located in a database), e.g., upon installation of thefemtocell, and then sent in a message (such as the ARM message describedherein) to the service provider. When the message is received, thatinformation may be mapped into propagation models maintained by theservice provider to derive, for example, the AP maximum transmit power.The variance between the typical and the actual residence layout and theactual location of the access terminal within the residence may becovered by the range of MSFDT_(DROP) and F2FDT_(DROP) parameters.

In 312, the access point base station may operate based on the secondinformation, e.g., the one or more operational parameters of the secondinformation. Operating according to the parameters may provide reducedinterference caused by the access point base station (e.g., in theoperation of neighboring macro or femto cells), and may allow forefficient handoffs between the access point base station and other basestations in the area (further descriptions provided below). Thus, theaccess point base station may be automatically configured or provisionedwithout requiring the user to manually configure the access point basestation, which typically requires a level of expertise greater than thatof average users.

In 314, in response to a change in the network, the access point basestation may receive updated operational parameters from the serviceprovider (e.g., automatically). Changes may include addition or removalof access point base stations, increases or decreases in load in thenetwork (e.g., causing the service provider to change various parametersto perform load balancing in the area), changes in environmentalconditions, detection of certain types of packages or messages in thenetwork, loss or decrease of power to various base stations, and/or anyother changes which may affect the parameters of the access point basestation.

In some embodiments, the change may be initially determined by theaccess point base station and reported to the service provider beforereceiving the updated operational parameters. However, in someembodiments, the service provider may provide the updated parameterswithout first receiving a message from the access point base station.For example, as indicated above, a new access point base station mayhave been added to the area, and in response to provisioning of the newaccess point base station, operational parameters of the access pointbase station may need to be changed, e.g., as determined by the serviceprovider. Accordingly, the access point base station may operate basedon the updated operational parameters, which may reduce interferencecaused by the access point base station in the changed network. Theupdated parameters may also allow for more efficient handoffs in thechanged network. Take the maximum transmit power parameter for example,in response to a change in the network, the access point base stationmay receive one or more updated power parameters. The one or moreupdated power parameters may comprise an updated maximum transmit powerparameter. The access point base station thus operates based on theupdated maximum transmit power parameter to reduce interference causedby the access point base station in the changed network.

Additionally, during operation, all overhead messages (such as PCH,etc.) may be rebroadcast in the access point base station coverage areato provide reliable delivery of pages during Idle HO. Furthermore, eachtime a new user and/or a new resource is added to the existing users(e.g., defined with the Channel Assignments Messages), the assignmentmay be indicated (e.g., sent over the OAM interface or over the air) tothe access point base station to aid in interference mitigation.

Note that various ones of the method elements described above (morespecifically, 304, 306, 308, 310, and/or 312) may be performedautomatically. As used herein, the term “automatically” is used to meanthat the actions are not performed by a user. For example, in thedescriptions above, a user may simply instruct the access point basestation to begin a provisioning procedure to set up the access pointbase station and the method elements described above may be performedwithout any further user input specifying the steps. Alternatively, theaccess point base station may automatically begin the set up as soon asthe access point base station is installed or otherwise coupled to thewide area network (e.g., the Internet). Thus, in this embodiment, theuser may not provide any input during the provisioning of the accesspoint base station. However, it should be noted that there may beembodiments where user input is required or requested during theautomatic process (e.g., confirmation of steps or requests for certainuser parameters).

FIGS. 6-9—Method for Performing Handoffs with an Access Point BaseStation

FIGS. 6-9 illustrate an exemplary method for performing handoffs with anaccess point base station. The method shown in these Figures may be usedin conjunction with any of the computer systems or devices shown in theabove Figures, among other devices. In various embodiments, some of themethod elements shown may be performed concurrently, performed in adifferent order than shown, or omitted. Additional method elements mayalso be performed as desired. As shown, this method may operate asfollows.

The described handoff methods may be immune to frequent switches betweenthe macro and access point base station environments (e.g., because theaccess point base station may be deployed anywhere within the macrocoverage area. For the cdma2000-1×RTT protocol, handoffs between themacro and access point base station environments may be controlled byexisting procedures specified in CDMA Tiered Services (User ZoneIdentification Messages, Private Neighbor List, Feature NotificationMessage, Flash With Information Message), the access point base stationaccess policy status or mode, the content of the preferred terminallist, and handoff request messages. Similarly, for the EV-DO or UMTSsystems, the handoff between the macro and access point base stationenvironments may be controlled by the access point base station accesspolicy, content of the preferred terminals list, and handoff requestsmessages.

In 602-606 of FIG. 6, the access point base station may be configured,e.g., according to the method described in FIG. 3. In 602, the accesspoint base station performs at least one measurement of signals receivedfrom the macro base station, and sends the measurement to the serviceprovider (in 604). In 604, the access point base station may receive HOparameters, such as macro to access point base station (or femto) dropthreshold “MSFDT_(DROP) ” and access point base station to macro dropthreshold “F2FDT_(DROP) ”, one or more hysteresis parameters, etc. fromthe service provider. Actually, the HO parameters may be established forthe access point base station during configuration or other times (e.g.,after network or environmental changes) by the service provider.

In 608, when the access terminal moves from the macro-to-access pointbase station, the access point base station may perform measurement ofsignals received from the access terminal. In the embodiment of FIG. 5,the access terminal may be currently given wireless services of theservice provider by a neighboring base station, such as a macro cellbase station. The access terminal may be within the coverage area of theaccess point base station or may be at least close enough that theaccess point base station may begin measuring or receiving signals fromthe access terminal. In some embodiments, the access terminal may be anaccess terminal defined on the preferred terminals list of the accesspoint base station, or may be an access terminal that is eligible toreceive access or services from the access point base station, e.g.,according to the admission policy information of the access point basestation.

In some embodiments, performing at least one measurement of signalsreceived by the access terminal may include the access terminaldetecting the access point base station and reporting signal strengthsreceived by the access terminal to the access point base station. Insome embodiments, the access terminal may measure the signal strength ofany base station it can communicate with/detect, and broadcast a messageindicating the detected base stations and/or their signal strengths bysignal measurement messages.

More specifically, in cdma2000-1×RTT systems, when the access terminaldetects the access point base station, it may send the PSMM message.After receiving a channel assignment message (CAM), both cell forwardlinks may be in the soft hand off (SHO). The access terminal may remainin the SHO until the access point base station signal strength ratiospecified by the macro to access point base station drop threshold(MSFDT_(DROP)) is reached. The MSFDT_(DROP) parameter is shown in FIG. 7with respect to the coverage areas of the macro-cell and the accesspoint base station. In this case, the M2FT drop parameter is indicatedwith dotted lines and occurs near the crossing of signal strengths (ofthe macro cell and the access point base station). Thus, theMSFDT_(DROP) parameter is used to indicate when handoffs should occurwhen an access terminal is handed off between a macro cell (or macrobase station) and an access point base station. Note that theMSFDT_(DROP) parameter may assume a positive (dB) value in order tocontrol the handoff and interference area. A ‘0’ value may effectivelydisable handoffs.

Similarly, for EV-DO or UMTS systems, when the access terminal detectsthe access point base station, it may send a cell measurement message,e.g., to the access point base station. Similar to above, the accesspoint base station may wait until MSFDT_(DROP) threshold is reached todetermine the HO completion.

In 610, the access point base station may determine whether the signalstrength is reached the signal strength specified by the MSFDT_(DROP).If the HO threshold is reached (MSFDT_(DROP)), the access point basestation may send a handoff request or handoff report to the serviceprovider (in 612), otherwise, go back to 610.

In 614, in response to the handoff request message, the macro cell basestation may be removed from the access terminal's active set, and theaccess point base station may provide service to this access terminal.Removal of the macro cell base station from the access terminal activeset may be performed by (or at the request of) the service providerand/or the access point base station, as desired. The active set of theaccess terminal may determine which base station the access terminaluses for network access. In this case, the macro base station may ceaseproviding service to this terminal which may continue using the accesspoint base station, thereby completing the handoff from the macro basestation to the access point base station.

Note that while the above described handoff procedure is facilitatedlargely by the access point base station, it is envisioned that thehandoff procedure may also be managed by other devices or servers, e.g.,by the service provider itself, such as, for example, a networkcontroller of the service provider. Thus, FIG. 5 describes a handoffprocedure for transferring provision of services to an access terminalfrom a macro base station to an access point base station. It should benoted that similar procedures may be used to perform handoffs betweendifferent access point base stations and/or other handoffs.

In 802 of FIG. 8, the access point base station may be configured, e.g.,according to the method described in FIG. 6. As indicated above, handoffparameters, such as macro to access point base station (or femto) dropthreshold “MSFDT_(DROP) ” and access point base station to macro dropthreshold “F2FDT_(DROP) ”, may be established for the access point basestation during configuration or other times (e.g., after network orenvironmental changes) by the service provider.

In 804, when the access terminal moves from the macro-to-access pointbase station, the access point base station may receive at least onemeasurement of signals received by at least one access terminal. In theembodiment of FIG. 9, the access terminal may be currently givenwireless services of the service provider by the access point basestation. The access terminal may be within the coverage area of aneighboring macro base station or may be at least close enough that themacro base station may be able to begin servicing the access terminal.

In some embodiments, performing at least one measurement of signalsreceived by the access terminal may include the access terminaldetecting the macro base station and/or reporting signal strengthsreceived by the access terminal to the access point base station. Forexample, in one embodiment, when the access terminal receives a signalfrom the macro base station at a strength above a specific threshold(e.g., a terminal add or TADD threshold), the access terminal may reportits strength in PSSM, RUM, or cell strength measurement messages.

More specifically, in cdma2000-1×RTT systems, when the access terminaldetects the macro base station, it may send the PSMM message. Afterreceiving a channel assignment message (CAM), the access point basestation may be added to this access terminal active set and, at thispoint, both cell forward links may be in the soft hand off (SHO). Theaccess terminal may remain in the SHO until the macro base stationsignal strength ratio specified by the access point base station tomacro drop threshold (F2FDT_(DROP)) is reached. The F2FDT_(DROP)parameter is shown in FIG. 9 with respect to the coverage areas of themacro cell and the access point base station (femtocell). In this case,the F2FDT_(DROP) parameter is indicated with dotted lines and occursnear the crossing of signal strengths (of the macro cell and the accesspoint base station). Thus, the F2FDT_(DROP) parameter is used toindicate when handoffs should occur when an access terminal is handedoff between an access point base station and a macro base station. Notethat the F2FDT_(DROP) parameter may assume a negative (dB) value inorder to control the handoff and interference area. A ‘0’ value mayeffectively disable handoffs.

Similarly, for EV-DO or UMTS systems, when the access terminal detectsthe macro base station, it may send a cell measurement message, e.g., tothe access point base station. Similar to above, the access point basestation may wait until F2FDT_(DROP) threshold is reached.

In 806, the access point base station may determine whether the signalstrength is reached the signal strength specified by the F2FDT_(DROP).If the HO threshold is reached (F2FDT_(DROP)), the access point basestation may send a handoff request or handoff report to the serviceprovider (in 808), otherwise, go back to 806.

In 810, in response to the handoff message, the access point basestation may be removed from the access terminal's active set and themacro base station will provide service to the access terminal. Removalof the access point base station from the access terminal active set maybe performed by (or at the request of) the service provider networkcontrol function and/or the access point base station, as desired. Theactive set of the access terminal may indicate which base station theaccess terminal may currently use for network access. In this case, theaccess terminal may cease to use the access point base station and maybegin using the macro base station for wireless communication, therebycompleting the handoff from access point base station to the macro basestation.

Note that while the above described handoff procedure is managed largelyby the access point base station, it is envisioned that the handoffprocedure may also be managed by other devices or servers, e.g., by thenetwork control function. Thus, FIG. 8 describes a handoff procedure fortransferring provision of services to an access terminal from an accesspoint base station to a macro base station. It should be noted thatsimilar procedures may be used to perform handoffs between differentaccess point base stations and/or other handoffs.

FIGS. 10—Method for Performing Admission Policy with an Access PointBase Station

In one embodiments, the first information which is sent to the serviceprovider during provisioning of an access point base station may includean access policy set. The access policy set may include a preferredterminal list and/or a service priority, for determining whether accessterminals can use the access point base station or for assigningpriority of access terminals for use of the access point base station.In some embodiments, the user may provide input (e.g., to a userinterface of the access point base station) for specifying the accessterminals of the preferred terminal list. Alternatively, oradditionally, users may enter in a secret code, e.g., using their accessterminal as an input device, to use (or get priority use of) the accesspoint base station. In some embodiments, the owner or administrator ofthe access point base station may define a priority (e.g., using tieredrankings, explicit ordering, or other methods) among the accessterminals in the list to define how the access point base station allotsresources to those access terminals on the list. However, it should benoted that the preferred terminal list may not be provided by the accesspoint base station during provisioning of the access point base station.For example, the preferred terminal list may be updated or provided bythe access point base station at any time after provisioning, asdesired.

Similarly, the access policy set may include an access policy mode. Forexample, the user may provide input of a desired access policy of theaccess point base station. In some embodiments, the access policy mayhave one or more of the following options: open (e.g., all accessterminals may access the access point base station), restricted (e.g.,all access terminals in the access terminal list are permittedunrestricted access where other access terminals have limited or noaccess), and/or private (e.g., only access terminals on the accessterminal list are allowed to use the access point base station). Similarto above, this information may or may not be provided duringprovisioning and may be provided or changed at any later point asdesired. However, in some embodiments, the user may not be able tocontrol the access policy of the access point base station; instead theservice provider may ultimately assign the policy. Thus, various typesof information may be provided to the service provider in the firstinformation.

Correspondingly, the second information sent by the service providerwill include admission policy information for controlling operating ofthe access point base station. The admission policy information mayinclude an admission policy mode parameter, which, as indicated above,may allow for open, restricted, or private access to the access pointbase station resources. Furthermore, the second information may includea preferred terminal list, which, as also indicated above, may be usedto manage service priority for access terminals. For example, in aprivate mode, the access point base station may restrict access only tothose access terminals on the list, where for a semi-open policy, thelisted access terminals may be given service while all other accessterminals may be given service according to the service priority. Theadmission policy mode and/or preferred terminal list may be determinedbased on the owner's service agreement, the location of the access pointbase station, the subscriptions of other customers near the location ofthe access point base station, the admission policy mode and/or apreferred terminal list provided by the access point base station (e.g.,as provided by the user), the neighbor list, and/or other information.

FIG. 10 illustrates an exemplary method for performing admission policywith an access point base station. In 902, the access point base stationmay receive a service request from an access terminal, for example, whenthe access terminal is moved from a macro base station to a positionclosely to the access point base station. In 904, the access point basestation determines whether the current admission policy mode is in open.If the admission policy mode in open, then provide service to the accessterminal (in 906). If not in the open mode, determine whether the accesspoint base station is in a restricted mode (in 908). If in therestricted mode, further determine whether the access terminal is on thepreferred list (in 910). As mentioned above, the listed access terminalwill be given unrestricted service (in 906), and the unlisted accessterminal will be given service according to the service priority (in912). If not in the restricted mode (N of step 908), determine whetherthe access point base station is in a private mode (in 914). If in theprivate mode, determine whether the access terminal is in the preferredlist (916). the listed access terminal will be given service whileservice request from unlisted access terminal will be ignored.

Although the embodiments above have been described in considerabledetail, numerous variations and modifications will become apparent tothose skilled in the art once the above disclosure is fully appreciated.It is intended that the following claims be interpreted to embrace allsuch variations and modifications.

1. A method for reducing interference to a network caused by an access point base station, the method comprising: performing at least one measurement of signals received by the access point base station; connecting to a service provider through a wired connection; transmitting first information to the service provider, wherein the first information comprises location information of the access point base station and the at least one measurement; receiving second information from the service provider, wherein the second information comprises one or more power parameters, the one or more power parameters comprising a maximum transmit power parameter, wherein the maximum transmit power parameter is determined based on the location information and the at least one measurement; and operating based on the maximum transmit power parameter, wherein said operating based on the maximum transmit power parameter reduces interference caused by the access point base station.
 2. The method of claim 1, wherein the maximum transmit power parameter defines a coverage area for the access point base station.
 3. The method of claim 1, wherein the access point base station is deployed in a first location having a first coverage area; wherein the maximum transmit power parameter is determined based on a coverage area propagation model.
 4. The method of claim 1, wherein the at least one measurement comprises signal measurements of a neighboring macro base station.
 5. The method of claim 1, wherein the method further comprises, in response to a change in the network: receiving updated second information from the service provider, wherein the updated second information comprises one or more updated power parameters, the one or more updated power parameters comprising an updated maximum transmit power parameter; and operating based on the updated maximum transmit power parameter, wherein said operating based on the updated maximum transmit power parameter reduces interference caused by the access point base station in the changed network.
 6. The method of claim 1, wherein the maximum transmit power parameter contains information specifying power allocation of one or more overhead channels.
 7. The method of claim 1, wherein the first information further comprises capability information of the access point base station; and wherein the maximum transmit power parameter is determined based on the capability information
 8. The method of claim 1, further comprising: receiving identity information from the service provider prior to the access point base station connecting to the service provider through the wired connection.
 9. The method of claim 1, wherein the access point base station is a femtocell.
 10. A femtocell, comprising: an interface for providing communication with one or more access terminals and a service provider; a processor coupled to the interface; a memory medium coupled to the processor, wherein the memory medium comprises program instructions executable to: perform at least one measurement of signals received by the femtocell using the interface; connect to the service provider through the interface; transmit first information to the service provider using the interface, wherein the first information comprises location information of the femtocell and the at least one measurement; receive second information from the service provider, wherein the second information comprises one or more power parameters, the one or more power parameters comprising a maximum transmit power parameter, wherein the maximum transmit power parameter is determined based on the location information and the at least one measurement; and operate based on the maximum transmit power parameter, wherein said operating based on the maximum transmit power parameter reduces interference caused by the femtocell.
 11. The femtocell of claim 10, wherein the maximum transmit power parameter defines a coverage area for the femtocell.
 12. The femtocell of claim 10, wherein the femtocell is deployed in a first location having a first coverage area; wherein the maximum transmit power parameter is determined based on a coverage area propagation model.
 13. The femtocell of claim 10, wherein the at least one measurement comprises signal measurements of a neighboring macro base station.
 14. The femtocell of claim 10, wherein, the program instructions are further executable to, in response to a change in the network: receive updated second information from the service provider, wherein the updated second information comprises one or more updated power parameters, the one or more updated power parameters comprising an updated maximum transmit power parameter; and operate based on the updated maximum transmit power parameter, wherein said operating based on the updated maximum transmit power parameter reduces interference caused by the access point base station in the changed network.
 15. The femtocell of claim 10, wherein the maximum transmit power parameter contains information specifying power allocation of one or more overhead channels.
 16. The femtocell of claim 10, wherein the first information further comprises capability information of the femtocell; wherein the maximum transmit power parameter is also determined based on the capability information
 17. The femtocell of claim 10, wherein the program instructions are further executable to: receive identity information from the service provider prior to the femtocell connecting to the service provider through the wired connection.
 18. A computer-accessible memory medium which stores program instructions for reducing interference to a network caused by an access point base station, wherein the program instructions are executable by a processor to: perform at least one measurement of signals received by the access point base station; connect to a service provider through a wired connection; transmit first information to the service provider, wherein the first information comprises location information of the access point base station and the at least one measurement; receive second information from the service provider, wherein the second information comprises one or more power parameters, the one or more power parameters comprising a maximum transmit power parameter, wherein the maximum transmit power parameter is determined based on the location information and the at least one measurement; and operate based on the maximum transmit power parameter, wherein said operating based on the maximum transmit power parameter reduces interference caused by the access point base station.
 19. A method for reducing interference to a network caused by an access point base station, the method comprising: receiving at least one measurement of signals and location information of the access point base station through a wired connection, wherein the at least one measurement of signals is received from the access point base station; determining and storing second information, wherein the second information comprises one or more power parameters, the one or more power parameters comprising a maximum transmit power parameter, wherein the maximum transmit power parameter is determined based on the location information and the at least one measurement; providing the second information to the access point base station, wherein the second information is usable by the access point base station to reduce interference caused by the access point base station.
 20. A communication system for providing wireless communication with one or more access terminals, comprising: a service provider; a macro base station for providing wireless communication with the one or more access terminals in a macro area; and an access point base station for providing wireless communication with the one or more access terminals in a local area intersected partially with the macro area, and wherein the access point base station is configured to: perform at least one measurement of signals received by the access point base station; connect to the service provider through a wired connection; transmit first information to the service provider, wherein the first information comprises location information of the access point base station and the at least one measurement; receive second information from the service provider, wherein the second information comprises one or more power parameters, the one or more power parameters comprising a maximum transmit power parameter, wherein the maximum transmit power parameter is determined based on the location information and the at least one measurement; and operate based on the maximum transmit power parameter, wherein said operating based on the maximum transmit power parameter reduces interference caused by the access point base station. 